Question

Give a reason why hydrogen might be placed along with the group lA elements of the periodic table.

Short answer

Hydrogen might be placed along with the group 1A elements in the periodic table because it shares similar properties, such as having one electron in the outermost shell, a valency of 1, and the ability to form positively-charged ions (cations) by losing this electron. The reactivity of hydrogen also resembles that of the group 1A elements.

Step-by-step solution

Identify properties of hydrogen

Hydrogen is the first element in the periodic table and has one electron in its outermost shell (1s1 configuration). It has a valency of 1 and forms a single covalent bond with other elements to achieve a stable configuration. Hydrogen can also lose this electron to form a positively-charged hydrogen ion (H+).

Identify properties of group 1A elements

Elements in group 1A of the periodic table (alkali metals) have one electron in their outermost shell (ns1 configuration, where n is the principal quantum number). They have a valency of 1 and are highly reactive, losing this electron to form positively-charged ions (cations).

Compare hydrogen to group 1A elements

Hydrogen and group 1A elements share the same valence electron configuration (having one electron in their outermost shell). They both have a valency of 1 and can form positively-charged ions by losing this electron. Their reactivity also arises from the desire to lose one electron and achieve a stable electronic configuration.

Reason for placing hydrogen in group 1A

Hydrogen might be placed along with the group 1A elements in the periodic table because it shares similar properties, such as having one electron in the outermost shell, a valency of 1, and the ability to form positively-charged ions (cations) by losing this electron. The reactivity of hydrogen also resembles that of the group 1A elements.

Key concepts

similarities with group 1A elements

Hydrogen is often discussed in relation to the group 1A elements, also known as alkali metals. This is not a random association. There are several similarities in their electronic structure and behavior. Both hydrogen and group 1A elements have a single electron in their outermost shell. For hydrogen, this is represented as a 1s¹ configuration, while for alkali metals it's ns¹, with 'n' being the shell number.

These elements share the same valency of 1, indicating they can form one bond with other elements. They can also each lose their one outer electron to form positively-charged ions, known as cations. This behavior is a key similarity, leading to their potential placement in the same group. Indeed, hydrogen's ability to mimic the electron loss that alkali metals undergo to achieve a noble gas configuration is a significant factor in this discussion.

• Both have one electron in their outer shell.
• Both can lose this electron to form a cation.
• Both share a valency of 1.

valency of hydrogen

Valency refers to the ability of an element to bond with other elements. Hydrogen's valency is 1, which is a critical aspect of its chemical behavior. This means it can form a single bond with another atom, which is represented in its chemical behavior.

Hydrogen can participate in covalent bonding, sharing its lone electron with another element to fill its outer shell. Covalent bonds are pretty common for hydrogen because it often undergoes sharing rather than ion formation. However, in some reactions, particularly with electronegative elements, hydrogen may forgo covalent bonding to form a hydrogen ion ( H⁺ ), evidencing its versatile nature.

The valency of 1 is central to its interactions and highlights its similarity to alkali metals, which also possess a single valency electron ready to engage in chemical reactions. This singular valency enables hydrogen to join the ranks of the highly reactive group 1A elements in the periodic table under certain contexts.

reactivity of hydrogen

The reactivity of hydrogen is a consequence of its electronic configuration and its desire to achieve a stable electron arrangement, akin to noble gases. With only one electron in its outer shell, hydrogen is eager to either share or lose this electron.

This reactivity mirrors the alkali metals' behavior. Group 1A elements are known for their intense reactivity, often reacting vigorously with water and other substances. Hydrogen's propensity to react stems from similar energetic demands; it actively seeks to participate in chemical reactions to stabilize its electronic configuration.

However, hydrogen's reactivity can show in two main ways: by forming covalent bonds, where electrons are shared, or in ionic reactions, where it forms hydrogen ions ( H⁺ ). Unlike some alkali metals that lean heavily towards forming ionic compounds, hydrogen's versatility also allows it to form stable covalent compounds. This dual reactivity highlights hydrogen's unique position and sometimes aligns it closer with non-metals than with the metals of group 1A.

• Can form either covalent bonds or hydrogen ions ( H⁺ ).
• Shoots for stabilization, just like alkali metals.